Category which adds keyed subscripting to NSUserDefaults

NSUserDefaults+Subscripting.h

//
//  NSUserDefaults+Subscripting.h
//
//  Created by Matt on 9/2/13.
//  Copyright (c) 2013 Matt Rajca. All rights reserved.
//

#import <Foundation/Foundation.h>

/* keys must be NSStrings */

@interface NSUserDefaults (Subscripting)

- (id)objectForKeyedSubscript:(id <NSCopying>)key;
- (void)setObject:(id)obj forKeyedSubscript:(id <NSCopying>)key;

@end

NSUserDefaults+Subscripting.m

//
//  NSUserDefaults+Subscripting.m
//
//  Created by Matt on 9/2/13.
//  Copyright (c) 2013 Matt Rajca. All rights reserved.
//

#import "NSUserDefaults+Subscripting.h"

@implementation NSUserDefaults (Subscripting)

- (id)objectForKeyedSubscript:(id <NSCopying>)key {
	if (![(NSObject *)key isKindOfClass:[NSString class]])
		return nil;
	
	return [self objectForKey:(NSString *)key];
}

- (void)setObject:(id)obj forKeyedSubscript:(id <NSCopying>)key {
	if (![(NSObject *)key isKindOfClass:[NSString class]])
		return;
	
	[self setObject:obj forKey:(NSString *)key];
}

@end